Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

☒ Rule 13d-1 (b)

☐ Rule 13d-1 (c)

☐ Rule 13d-1 (d)

*

The remainder of this cover page shall be filled out for a reporting persons initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information
which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be
deemed to be filed for the purpose of Section 18 of the Securities Exchange Act of 1934 (the Act) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act
(however, see the Notes.)

Item 3. If this statement is filed pursuant to § 240.13d-1(b), or §
240.13d-2(b) or (c), check whether the person filing is a:

Warren E. Buffett (an individual
who may be deemed to control Berkshire Hathaway Inc.), Berkshire Hathaway Inc. and GEICO Corporation are each a Parent Holding Company or Control Person, in accordance with § 240.13d-1(b)(1)(ii)(G).

National Indemnity Company, Government Employees Insurance Company and GEICO Indemnity Company are each an Insurance Company as defined in
section 3(a)(19) of the Act.

Provide the following information regarding the aggregate number and percentage of the class of securities of the issuer identified in Item 1.

(a)

Amount beneficially Owned

See the Cover Pages for each of the Reporting Persons.

(b)

Percent of Class

See the Cover Pages for each of the Reporting Persons.

(c)

Number of shares as to which such person has:

(i)

sole power to vote or to direct the vote

(ii)

shared power to vote or to direct the vote

Page 11 of 14 Pages

(iii)

sole power to dispose or to direct the disposition of

(iv)

shared power to dispose or to direct the disposition of

See the Cover Pages for each of the
Reporting Persons.

Item 5. Ownership of Five Percent or Less of a Class.

Not Applicable.

Item 6. Ownership of
More than Five Percent on Behalf of Another Person.

Not Applicable.

Item 7. Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company or Control
Person.

See Exhibit A.

Item 8.
Identification and Classification of Members of the Group.

See Exhibit A.

Item 9. Notice of Dissolution of Group.

Not Applicable.

Item 10. Certification.

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held
in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a
participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

Page 12 of 14 Pages

SIGNATURES

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true,
complete and correct.

Warren E. Buffett (an individual who may be deemed to control Berkshire Hathaway Inc.)

Berkshire Hathaway Inc.

GEICO
Corporation

INSURANCE COMPANIES AS DEFINED IN SECTION 3(a)(19) OF THE ACT:

National Indemnity Company

Government Employees Insurance Company

GEICO Indemnity Company

EMPLOYEE BENEFIT PLANS
IN ACCORDANCE WITH § 240.13d-1-(b)(1)(ii)(F)

Precision Castparts Corp. Master Trust

SCHEDULE 13G

EXHIBIT B

JOINT
FILING AGREEMENT PURSUANT TO RULE 13d-1(k)(1)

The undersigned persons hereby agree that
reports on Schedule 13G, and amendments thereto, with respect to the Common Stock of United Continental Holdings, Inc. may be filed in a single statement on behalf of each of such persons, and further, each of such persons designates Warren E.
Buffett as its agent and Attorney-in-Fact for the purpose of executing any and all Schedule 13G filings required to be made by it with the Securities and Exchange
Commission.